<?xml version="1.0" encoding="utf-8" ?>
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui" onLoad="Ribbon_Load" >
  <ribbon>
    <tabs>
      <tab id="MyTab" label="My Tab">
        <group id="MyGroup" label="My Group">
          <button id="MyButton" label="My Button" onAction="OnAction" />
        </group>
      </tab>
    </tabs>
  </ribbon>
</customUI>